"Jackass" star Ryan Dunn and his passenger, Zachary Hartwell, were killed by blunt-force trauma and flames after Dunn's Porsche went over a guard rail, hit a tree, and burst into flames, a coroner's report concluded.

West Goshen, Pa., police arrived around 2:38 a.m. Monday, and the two were declared dead at the scene, the Chester County Coroner's Office told TheWrap.

There is no finding yet on whether alcohol was a factor in the crash, but police said speed was believed to be a cause.

The Philadelphia Inquirer reported that Dunn had 23 driving citations, including a DUI, in the 13 years before his death. A man who drank with Dunn in the hours before his crash, meanwhile, described a binge in which Dunn had four shots and beer before getting behind the wheel.